Perl Module using %EXPORT_TAGS -

i'm having trouble using %export_tags in perl module. in solver.pl have:

use matrixfunctions qw(:normal); 

then inside matrixfunctions.pm, have:

package matrixfunctions;  use strict; use exporter; use vars qw($version @isa @export @export_ok %export_tags);  $version     = 1.00; @isa         = qw(exporter); @export      = (); @export_ok   = qw(&det &identitymatrix &matrixadd      &matrixscalarmultiply &matrixmultiplication); %export_tags = ( det => [qw(&det)],     normal => [qw(&det &identitymatrix &matrixadd          &matrixscalarmultiply &matrixmultiplication)]); 

however works when have @export_ok including methods. if have

@export_ok   = (); 

i have error:

"matrixscalarmultiply" not exported matrixfunctions module  "det" not exported matrixfunctions module  "matrixadd" not exported matrixfunctions module  "matrixmultiplication" not exported matrixfunctions module  "identitymatrix" not exported matrixfunctions module can't continue after import errors @ solver.pl line 6. begin failed--compilation aborted @ solver.pl line 6. 

the point of using qw(:normal) in solver.pl file can have @export_ok empty thought. doing wrong?

perldoc -f exporter under advanced features section:

e.g., module.pm defines:

@export = qw(a1 a2 a3 a4 a5); @export_ok = qw(b1 b2 b3 b4 b5); %export_tags = (t1 => [qw(a1 a2 b1 b2)], t2 => [qw(a1 a2 b3 b4)]); 

note cannot use tags in @export or @export_ok.

names in export_tags must appear in @export or @export_ok.

the bolded section above explains required have functions wish place in %export_tags in either @export_ok or @export

a pattern have started using defined want allow exported in @export_ok, use @export_ok build `:all' tag:

our @isa = qw(exporter); our @export_ok = qw/raspberry apple/;  our %export_tags = (     'all' => \@export_ok, );